Abstract

The construction of a single-photon source by use of gated parametric fluorescence is reported with the measurement results of the photon number distribution. A beamlike twin-photon method is used in order to achieve high-collection efficiency. The estimated probability P(1) to find a single photon in a collimated output pulse is 26.5% at a repetition rate of 10 kHz when the effective quantum efficiency of 27.4% in the detection setup is compensated.

For example, a single-photon source with the photon number distribution {P(0), P(1), P(2)} = {0.7, 0.3, 0} is much more useful for quantum cryptography than that with {0.5, 0.4, 0.05}, where P(n) is the probability to find n photons in a pulse. Those photon number distributions, however, yield the same Fano factor F = 0.7.

S. Takeuchi, “Twin photon beams for the single photon generation,” in Proceedings of the 7th International Symposium on Foundations of Quantum Mechanics in the Light of New Technology, ISQM-Tokyo ’01 (World Scientific, Teaneck, N.J., 2002), pp. 98–103.
[CrossRef]

Takeuchi, S.

S. Takeuchi, “Twin photon beams for the single photon generation,” in Proceedings of the 7th International Symposium on Foundations of Quantum Mechanics in the Light of New Technology, ISQM-Tokyo ’01 (World Scientific, Teaneck, N.J., 2002), pp. 98–103.
[CrossRef]

Other (6)

For example, a single-photon source with the photon number distribution {P(0), P(1), P(2)} = {0.7, 0.3, 0} is much more useful for quantum cryptography than that with {0.5, 0.4, 0.05}, where P(n) is the probability to find n photons in a pulse. Those photon number distributions, however, yield the same Fano factor F = 0.7.

S. Takeuchi, “Twin photon beams for the single photon generation,” in Proceedings of the 7th International Symposium on Foundations of Quantum Mechanics in the Light of New Technology, ISQM-Tokyo ’01 (World Scientific, Teaneck, N.J., 2002), pp. 98–103.
[CrossRef]

Figures (2)

Schematic of the experimental setup. A signal photon and a control photon are created at the same time in a β-barium borate crystal. The control photons were detected directly by a single-photon detector, while the signal photons were guided into an optical fiber delay line. Then the signal photons were gated by the fast optical shutter. This shutter opens only when the first detection event of the control photon is observed in each pulse (time window of 100 μs) and blocks other photons in the same pulse.

(a) Photon number distribution of the output state. P(1) and P(2) show the probability of finding one or two photons in an output pulse (100 μs), respectively. We counted the number of detection events in each pulse and estimated a photon number distribution at the output of our source, as described in the text. (b) Photon number distribution of weak coherent light with the same average photon number of (a). (c) Photon number distribution of weak coherent light with the same P(2) of (a).